1. Field of the Invention
The invention relates to a shoe sole, in particular for sports shoes.
2. Description of the Related Art
In a known shoe sole (German patent specification No. 829 265), the tread surface of the sole is formed by a tube element which is arranged on the foresole and which can be inflated by means of an air pump. A valve fitment is disposed in the arch region on the underside of the sole for inflating the tube element. A recess is provided in which the valve can be disposed when not in use. The tube element forms a closed ring and is contoured to approximately correspond to the contour of the edge of the foresole and extends parallel thereto. The tube element defines a single closed chamber. The result is that in the course of the rolling movement associated with walking or running, the weight of the user causes air to be displaced out of the part of the tube element which is primarily subjected to a loading and into the less heavily loaded part thereof. That displaced air can result in a floating feeling which gives rise to instability. In order to correct that, the tube element can be inflated to a relatively high pressure, but it then loses its soft tread action which is desired for a damping effect.
In another known shoe sole (U.S. Pat. No. 2,605,560), the ground-engaging side of the foresole and the heel portion are each formed by a respective air cushion which, with the exception of a narrow edge region, occupies the entire surface area of the foresole and the heel portion respectively. Unlike a tube element in the above-described known shoe sole whose width is small in relation to the width of the sole, each air cushion in that known shoe sole bears against the ground practically over the width of the sole and in an undefined fashion. As a result, the tendency of air to be displaced from a loaded region of the air cushion to a less loaded region thereof is made still more pronounced and there is no guarantee that the foot is satisfactorily guided in its rolling movement.